The present invention is generally related to medical devices, kits, and methods. More specifically, the present invention provides a system for crossing stenosis, partial occlusions, or total occlusions in a patient""s body.
Cardiovascular disease frequently arises from the accumulation of atheromatous material on the inner walls of vascular lumens, particularly arterial lumens of the coronary and other vasculature, resulting in a condition known as atherosclerosis. Atheromatous and other vascular deposits restrict blood flow and can cause ischemia which, in acute cases, can result in myocardial infarction or a heart attack. Atheromatous deposits can have widely varying properties, with some deposits being relatively soft and others being fibrous and/or calcified. In the latter case, the deposits are frequently referred to as plaque. Atherosclerosis occurs naturally as a result of aging, but may also be aggravated by factors such as diet, hypertension, heredity, vascular injury, and the like.
Atherosclerosis can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches which rely on intravascular widening or removal of the atheromatous or other material occluding the blood vessel. Particular catheter-based interventions include angioplasty, atherectomy, laser ablation, stenting, and the like. For the most part, the catheters used for these interventions must be introduced over a guidewire, and the guidewire must be placed across the lesion prior to catheter placement. Initial guidewire placement, however, can be difficult or impossible in tortuous regions of the vasculature. Moreover, it can be equally difficult if the lesion is total or near total, i.e. the lesion occludes the blood vessel lumen to such an extent that the guidewire cannot be advanced across.
To overcome this difficulty, forward-cutting atherectomy catheters have been proposed. Such catheters usually can have a forwardly disposed blade (U.S. Pat. No. 4,926,858) or rotating burr (U.S. Pat. No. 4,445,509). While effective in some cases, these catheter systems, even with a separate guidewire, have great difficulty in traversing through the small and tortuous body lumens of the patients and reaching the target site.
For these reasons, it is desired to provide devices, kits, and methods which can access small, tortuous regions of the vasculature and which can remove atheromatous, thrombotic, and other occluding materials from within blood vessels. In particular, it is desired to provide atherectomy systems which can pass through partial occlusions, total occlusions, stenosis, and be able to macerate blood clots or thrombotic material. It is further desirable that the atherectomy system have the ability to infuse and aspirate fluids before, during, or after crossing the lesion. At least some of these objectives will be met by the devices and methods of the present invention described hereinafter and in the claims.
The present invention provides systems and methods for removing occlusive material and passing through occlusions, stenosis, thrombus, and other material in a body lumen. More particularly, the present invention can be used passing through stenosis or occlusions in a neuro, cardio, and peripheral body lumens. Generally, the present invention includes an elongate member that is positioned adjacent the occlusion or stenosis. A drive shaft having a distal tip is rotated and advanced from within the elongate member to create a path forward of the elongate member to form a path in the occlusion or stenosis. To facilitate passing through the occlusion or stenosis, the distal end of the elongate member can be steerable to provide better control the creation of the path through the occlusion or stenosis. Optionally, the target site can be infused and/or aspirated before, during, and after creation of the path through the occlusion.
In an exemplary embodiment, the elongate member is a hollow guidewire that has a flexibility, pushability and torqueability to be advanced through the tortuous blood vessel without the use of a separate guidewire. Additionally, the hollow guidewire may be sized to fit within a conventional support or access catheter system and inserted into the blood vessel and delivered to the target site. The catheter system can be delivered either concurrently with the advancement of the hollow guidewire or after the guidewire has reached the target site. The position of the hollow guidewire and catheter system can be maintained and stabilized while the drive shaft is rotated and translated out of the axial lumen of the hollow guidewire. The distal tip of the drive shaft can be deflected, coiled, blunted, flattened, enlarged, twisted, basket shaped, or the like. In some embodiments, to increase the rate of removal of the occlusive material, the distal tip is sharpened or impregnated with an abrasive material such as diamond chips, diamond powder, glass, or the like.
The drive shaft can be a counter-wound guidewire construction or be of a composite structure consisting of a fine wire around which a coil is wrapped. The counter-wound or composite constructions are more flexible than a single wire drive shaft and can provide a fighter bending radius while still retaining the torque transmitting ability so that it can still operate as a lesion penetration mechanism.
In a specific configuration, the drive shaft has spiral threads or external riflings extending along the shaft. The spirals typically extend from the proximal end of the shaft to a point proximal of the distal tip. As the drive shaft is rotated and axially advanced into the occlusive material, the distal tip creates a path and removes the material from the body. The rotating spirals act similar to an xe2x80x9cArchimedes Screwxe2x80x9d and transport the removed material proximally up the lumen of the elongate member and prevent the loose atheromatous material from escaping into the blood stream.
Systems and kits of the present invention can include a support system or access system, such as a catheter or guidewire having a body adapted for intraluminal introduction to the target blood vessel. The dimensions and other physical characteristics of the access system body will vary significantly depending on the body lumen which is to be accessed. In the exemplary case, the body of the support or access system is very flexible and is suitable for introduction over a conventional guidewire or the hollow guidewire of the present invention. The support or access system body can either be for xe2x80x9cover-the-wirexe2x80x9d introduction or for xe2x80x9crapid exchange,xe2x80x9d where the guidewire lumen extends only through a distal portion of the access system body. Optionally, the support or access system can have at least one axial channels extending through the lumen to facilitate infusion and/or aspiration of material from the target site. Support or access system bodies will typically be composed of an organic polymer, such as polyvinylchloride, polyurethanes, polyesters, polytetrafluoroethylenes (PTFE), silicone rubbers, natural rubbers, or the like. Suitable bodies may be formed by extrusion, with one or more lumens that extend axially through the body. For example, the support or access system can be a support catheter, interventional catheter, balloon dilation catheter, atherectomy catheter, rotational catheter, extractional catheter, laser ablation catheter, guiding catheter, stenting catheter, ultrasound catheter, and the like.
In other embodiments, a hollow guidewire can be used as the support or access system. The hollow guidewire can be navigated to and positioned at the target site, with or without the use of a separate guidewire. The hollow guidewire support system provides the flexibility, maneuverability, torqueability (usually 1:1), and columnar strength necessary for accurately advancing through the tortuous vasculature. The hollow guidewire support system can act as a working channel inside of which other interventional devices can be delivered to the target site. Such devices include, but are not limited to a rotating guidewire, infusion guidewire, clot maceration guidewire, normal guidewire, and the like. Because the hollow guidewire is not composed of polymer, the hollow guidewire working channel does not soften at body temperatures.
The hollow guidewire working channel typically has a thin wall construction which allows the lumen of the working channel to be maximized when compared with polymeric based catheter designs. This allows larger diameter devices to be inserted into it than can inserted through similar sized catheter-based devices. The larger lumen of the hollow guidewire working channel allows devices such as clot macerators and other larger devices to be delivered to the target lesion. Additionally the larger diameter lumen allows infusion of clot dissolving fluid and/or aspiration of the debris created in the clot maceration process.
In use, the access system can be delivered to the target site over a conventional guidewire. Once the access system has been positioned near the target site, the conventional guidewire can be removed and the elongate member can be advanced through the access system to the target site. Alternatively, because the elongate member can have the flexibility, pushability, and torqueability to be advanced through the tortuous regions of the vasculature, it is possible to advance the elongate member through the vasculature to the target site without the use of a separate guidewire. The access system can be advanced over the elongate member to the target site. Once the elongate member has been positioned at the target site, the drive shaft is rotated and advanced into the occlusive material. The rotation of the distal tip creates a path forward of the elongate member. In some embodiments the path created by the distal tip has a path radius which is larger than the radius of the distal end of the elongate member. In other embodiments, the path created by the distal tip has a path radius which is the same size or smaller than the radius of the elongate member.
One exemplary system for crossing an occlusion or stenosis within a body lumen comprises a drive shaft that is rotatably and translatably received within an axial lumen of an elongate member. Means at a distal portion of the drive shaft creates a path in front of the elongate member to facilitate crossing of the occlusion or stenosis. The means is moveable between an axially retracted configuration and an axially extended configuration. The means in the axially extended configuration creates a profile that is at least as large as the diameter of the distal end of the elongate member. In alternative implementations, the path creating means can move from the retracted position to an extended configuration that has a profile with the same or smaller profile than the distal end of the elongate member.
In another aspect, the present invention provides a system for crossing an occlusion or stenosis within a body lumen. The system comprises an elongate member having a proximal end, a distal end, and a lumen. A drive shaft is rotatably and translatably disposed in the elongate member and is removably attached to a rotating mechanism. The rotating mechanism rotates the drive shaft so that a distal tip can be advanced beyond the distal end of the elongate member to create a path through the occlusion or stenosis such that the elongate member can be advanced past the occlusion or stenosis. In a specific implementation, the rotating mechanism can be detached from the drive shaft and an access system can be delivered to the target site over the elongate member. Thereafter, the rotating mechanism can be reattached and the drive shaft can be rotated.
In yet another aspect, the present invention provides an assembly for crossing an occlusive or stenotic material in a body lumen. The assembly comprises a guidewire having an axial lumen. A drive shaft rotatably and translatably extends through the axial lumen of the guidewire. The drive shaft has a distal tip that can be rotated and advanced to create a path through the occlusive or stenotic material. In some embodiments, the guidewire has an outer diameter or periphery similar to conventional passive guidewires used for neuro, cardio, and peripheral interventions. The outer diameter or periphery of the guidewire having an axial lumen is typically between approximately 0.040 inches and 0.009 inches, and preferably between approximately 0.024 inches and 0.009 inches, and typically between 0.013 and 0.014 inches. Depending on the body lumen that is accessed, the outer diameter of the guidewire can be larger or smaller. In most embodiments, the guidewire has the torqueability, pushability, and steerability to be advanced through the body lumen.
In yet another aspect the present invention provides a guidewire system for passing through occlusions or stenosis. The system comprises a hollow guidewire having a distal end, a proximal end, and a lumen. A drive shaft is movably disposed within the hollow guidewire such that a distal tip portion can extend beyond the distal end of the hollow guidewire. A rotating mechanism can rotate the drive shaft and an actuator can be used to control the axial movement of the drive shaft. Activation of the actuator moves the distal end of the rotating drive shaft along its longitudinal axis to create a path through the occlusion or stenosis.
In yet another aspect, the present invention provides a method of crossing an occlusion or stenosis within a body lumen. The method comprises positioning an elongate member and a drive shaft in the body lumen. The drive shaft is rotated. The drive shaft is expanded from a retracted configuration to an expanded configuration. In the expanded configuration, the drive shaft creates a path that is at least as large as the perimeter of the distal end of the elongate member. The distal portion of the drive shaft is then advanced into the occlusion or stenosis to create a path in the occlusion or stenosis.
In another aspect the present invention provides a method of crossing an occlusion or stenosis within a body lumen. The method comprises advancing a guidewire through the body lumen. An access or support system is moved over the guidewire to the occlusion or stenosis. The guidewire is removed from the body lumen and a steerable elongate member having a drive shaft is passed through the lumen of the access system. The drive shaft is rotated within a lumen of the elongate member. The drive shaft is advanced from a retracted position to an extended position to create a path through the occlusion or stenosis.
In yet another aspect, the present invention provides a method of passing through an occlusive or stenotic material in a body lumen. The method comprises positioning a hollow guidewire with a drive shaft adjacent the occlusion. A drive shaft is rotated and advanced out of the hollow guidewire and into the occlusive or stenotic material to create a path through the occlusive or stenotic material. In some embodiments, the guidewire can then be moved through the occlusive or stenotic material and an access system can be positioned in the path through the occlusive or stenotic material. The remaining occlusive or stenotic material can then removed with the access system.
In another aspect, the present invention provides a kit. The kit has a hollow guidewire having a lumen. A rotatable drive shaft having a shaped distal tip is removably received within the lumen of the hollow guidewire. Instructions for use in passing occlusions or stenosis in a body lumen comprise rotating the inner wire within the steerable hollow guidewire and advancing the drive shaft into the occlusive or stenotic material to create a path through the occlusive or stenotic material. A package is adapted to contain the hollow guidewire, rotatable wire, and the instructions for use. In some embodiments, the instructions can be printed directly on the package, while in other embodiments the instructions can be separate from the package.
These and other aspects of the invention will be further evident from the attached drawings and description of the invention.